video: Make white-on-black a video-device property

The CONFIG_WHITE_ON_BLACK setting is hard-coded at build-time. It is
useful to be able to control this when showing menus.

Create a property to hold this information, using the CONFIG as the
initial value.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/boot/expo.c b/boot/expo.c
index 786f665..8ce645e 100644
--- a/boot/expo.c
+++ b/boot/expo.c
@@ -194,7 +194,7 @@
 	u32 colour;
 	int ret;
 
-	back = CONFIG_IS_ENABLED(SYS_WHITE_ON_BLACK) ? VID_BLACK : VID_WHITE;
+	back = vid_priv->white_on_black ? VID_BLACK : VID_WHITE;
 	colour = video_index_to_colour(vid_priv, back);
 	ret = video_fill(dev, colour);
 	if (ret)
diff --git a/boot/scene.c b/boot/scene.c
index 3290a40..15e7a8b 100644
--- a/boot/scene.c
+++ b/boot/scene.c
@@ -330,8 +330,9 @@
 	enum colour_idx fore, back;
 	uint inset = theme->menu_inset;
 
+	vid_priv = dev_get_uclass_priv(dev);
 	/* draw a background for the object */
-	if (CONFIG_IS_ENABLED(SYS_WHITE_ON_BLACK)) {
+	if (vid_priv->white_on_black) {
 		fore = VID_DARK_GREY;
 		back = VID_WHITE;
 	} else {
@@ -344,7 +345,6 @@
 		return;
 
 	vidconsole_push_colour(cons, fore, back, &old);
-	vid_priv = dev_get_uclass_priv(dev);
 	video_fill_part(dev, label_bbox.x0 - inset, label_bbox.y0 - inset,
 			label_bbox.x1 + inset, label_bbox.y1 + inset,
 			vid_priv->colour_fg);
@@ -408,7 +408,8 @@
 			struct vidconsole_colour old;
 			enum colour_idx fore, back;
 
-			if (CONFIG_IS_ENABLED(SYS_WHITE_ON_BLACK)) {
+			vid_priv = dev_get_uclass_priv(dev);
+			if (vid_priv->white_on_black) {
 				fore = VID_BLACK;
 				back = VID_WHITE;
 			} else {
@@ -416,7 +417,6 @@
 				back = VID_BLACK;
 			}
 
-			vid_priv = dev_get_uclass_priv(dev);
 			if (obj->flags & SCENEOF_POINT) {
 				vidconsole_push_colour(cons, fore, back, &old);
 				video_fill_part(dev, x - theme->menu_inset, y,
diff --git a/drivers/video/video-uclass.c b/drivers/video/video-uclass.c
index 503cdb9..1c372bd 100644
--- a/drivers/video/video-uclass.c
+++ b/drivers/video/video-uclass.c
@@ -345,7 +345,7 @@
 	struct video_priv *priv = dev_get_uclass_priv(dev);
 	int fore, back;
 
-	if (CONFIG_IS_ENABLED(SYS_WHITE_ON_BLACK)) {
+	if (priv->white_on_black) {
 		/* White is used when switching to bold, use light gray here */
 		fore = VID_LIGHT_GRAY;
 		back = VID_BLACK;
@@ -582,6 +582,18 @@
 	video_sync_all();
 }
 
+void video_set_white_on_black(struct udevice *dev, bool white_on_black)
+{
+	struct video_priv *priv = dev_get_uclass_priv(dev);
+
+	if (priv->white_on_black != white_on_black) {
+		priv->white_on_black = white_on_black;
+		video_set_default_colors(dev, false);
+
+		video_clear(dev);
+	}
+}
+
 /* Set up the display ready for use */
 static int video_post_probe(struct udevice *dev)
 {
@@ -624,6 +636,8 @@
 	if (IS_ENABLED(CONFIG_VIDEO_COPY) && plat->copy_base)
 		priv->copy_fb = map_sysmem(plat->copy_base, plat->size);
 
+	priv->white_on_black = CONFIG_IS_ENABLED(SYS_WHITE_ON_BLACK);
+
 	/* Set up colors  */
 	video_set_default_colors(dev, false);
 
diff --git a/include/video.h b/include/video.h
index 2fe2f73..0ec6b1c 100644
--- a/include/video.h
+++ b/include/video.h
@@ -100,6 +100,7 @@
  * @fg_col_idx:	Foreground color code (bit 3 = bold, bit 0-2 = color)
  * @bg_col_idx:	Background color code (bit 3 = bold, bit 0-2 = color)
  * @last_sync:	Monotonic time of last video sync
+ * @white_on_black: Use a black background
  */
 struct video_priv {
 	/* Things set up by the driver: */
@@ -131,6 +132,7 @@
 	u8 fg_col_idx;
 	u8 bg_col_idx;
 	ulong last_sync;
+	bool white_on_black;
 };
 
 /**
@@ -347,6 +349,16 @@
 void video_set_default_colors(struct udevice *dev, bool invert);
 
 /**
+ * video_set_white_on_black() - Change the setting for white-on-black
+ *
+ * This does nothing if the setting is already the same.
+ *
+ * @dev: video device
+ * @white_on_black: true to use white-on-black, false for black-on-white
+ */
+void video_set_white_on_black(struct udevice *dev, bool white_on_black);
+
+/**
  * video_default_font_height() - Get the default font height
  *
  * @dev:	video device